1. Field
The present aspects of the disclosed embodiments relates for systems for handling and storing biological or chemical samples, and more specifically to an automated system for storage, retrieval and management of large numbers of samples retained in sealed arrays of storage containers.
2. Brief Description of Related Developments
Many scientific and medical organizations, including industrial concerns, regulatory agencies, research laboratories, and academic institutions, have the need for secure storage of very large numbers, e.g., a few thousand up to multiple millions, of samples and specimens. Such fields include pharmaceutical, biotechnology, laboratory diagnostics, genomics, biospecimen, forensic, agrichemical and specialty chemical. Depending on the application, the sample sizes can vary from tens of microliters to several drams, which are stored in small, sealed plastic tubes or vials. These containers are retained in a rack that allows individual samples to be inserted or removed without removing an entire rack, or the tray the holds one or more racks. To extend the useful lifetime of the samples, they are stored in a controlled environment of low temperature (typically −20° to −80° C. or lower), low humidity, and inert gas (nitrogen), and are subjected to as little environmental variation as possible. In order to handle very large numbers of samples in the most efficient manner, a number of considerations must be made to enhance the system's flexibility and adaptability for different applications with the smallest possible footprint to minimize the use of valuable laboratory space.
An overview of currently available compound storage systems and technologies is provided by Dr. John Comley in his article entitled “Compound Management in pursuit of sample integrity”, published in Drug Discovery World, Spring 2005, pp. 59-78, which is incorporated herein by reference.
Tracking of the samples is essential, and the sample containers, racks and trays are usually labeled with a bar code or other machine-readable identifier. The identity and location of each sample is stored in a system memory that maintains records for all samples in the storage system so that individual samples or subsets of samples can be identified and rapidly retrieved from storage. Ideally, the retrieval process should occur without unnecessarily exposing samples to thawing or moisture, which means that the system must be capable of selecting individual samples from one or more racks in the storage compartment while minimizing exposure of other samples in the storage compartment, or in the same trays, to an environmental change. It is also important that the system be reliable so that it can be serviced without risking exposure of the samples to undesirable conditions.
To prevent evaporation of the sample or exposure to contaminants during storage, the containers are usually covered with a cap or membrane stretched across the open end of the container. In order to deal efficiently with the large numbers of containers in a tray, systems are commercially available to simultaneously seal all containers within the tray with a sheet of material, such as foil or laminated polymer, that is heat sealed or otherwise adhered to the top edges of all of the containers. These seals are pierceable or peelable to permit access to the sample. After the containers are sealed, the excess seal material between the containers is cut to separate the individual containers for subsequent retrieval without requiring the entire tray of containers to be thawed. After die cutting of the seals, the tray of containers is placed in storage. The die cutting operation requires a separate handling step, and usually, an additional piece of equipment with complex tooling that is specifically designed for a certain size and shape of tube, thus limiting the type of containers that can be used, or requiring that multiple die cutting tools be available.
In certain applications, the samples are preferably stored at ultra-low temperatures (−80° C. or lower), however, this cold environment can be hazardous to the electro-mechanical devices that are necessary for operation of an automated system. Lubricants are less effective at such low temperatures, making the robotics less reliable. Maintenance of robotics in the sample storage area is particularly a problem because the storage environment must be thawed and opened, subjecting the samples to condensation and possible thawing. Some commercial systems isolate the robotics in a somewhat warmer compartment (−20° C.), passing the samples between the two compartments. In such systems, an insulating wall must be created between the two compartments to maintain the temperatures in each compartment.
In existing systems, the sample storage areas have removable doors that are opened to obtain access to the trays. In others, the trays (or stacks of trays), have a block of insulating material at one end so that all trays together combine to form an insulated wall. When a tray is removed, the insulating material associated with that tray is also removed and must be replaced with a dummy block to maintain the integrity of the insulating wall. This replacement process takes time, however, increasing the risk of temperature change in one or both compartments.
In large storage applications, the samples may need to be accessed by multiple groups whose laboratory areas are in different locations within a facility, possibly even on different floors of a multi-story building. Access for loading and unloading sample containers in existing compound storage systems is located at a single location at the base of the storage unit. This often results in transporting large numbers of samples on carts and potentially exposing them to undesirable conditions. Further, with all groups needing to access their samples from a single station, time will be lost waiting for another user to finish their sample storage or retrieval operation.
Many prior art storage systems utilize a gantry-style robotic conveyor, which provides horizontal and vertical control of the positioning of a tray handler for extracting and replacing trays within the storage compartment. An example of such a system is described in U.S. Pat. No. 6,663,334, which is incorporated herein by reference. The conveyor often includes a horizontal rail on with a vertical beam rides, driven by a motor and a screw or chain drive mechanism at the bottom of the vertical beam. In some systems, an upper guide rail may be provided to maintain the correct orientation of the vertical beam, particularly where the storage racks are tall. In the system described in the '334 patent, the conveyor employs a loop drive belt that is driven by a motor at the bottom of the conveyor. The vertical lift utilizes a separate set of drive belts. Certain disadvantages of current systems include the amount of room required for the conveyor assembly. The footprint of the overall system is preferably as small as possible to minimize use of valuable laboratory space. Therefore, it would be desirable to reduce the size of the conveyor enclosure as much as possible.
the present aspects of the disclosed embodiments is directed to storage systems that address the foregoing concerns to provide the flexibility and ease of use of large volume sample storage system.